Scattered Nuclear Staining: A Novel Immunohistochemical Expression Pattern of Mismatch Repair Proteins and Its Significance in Endometrial Carcinoma

Scattered Nuclear Staining: A Novel Immunohistochemical Expression Pattern of Mismatch Repair Proteins and Its Significance in Endometrial Carcinoma | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Scattered Nuclear Staining: A Novel Immunohistochemical Expression Pattern of Mismatch Repair Proteins and Its Significance in Endometrial Carcinoma Qiujuan Huang, Qing Li, Yutian Wang, Jing Luan, Bo Yang, Lisha Qi, and 10 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8078986/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 10 You are reading this latest preprint version Abstract Background Immunohistochemical (IHC) analysis of mismatch repair (MMR) proteins is a widely accepted method for the routine screening of microsatellite instability (MSI) in endometrial carcinoma (EC). However, IHC may occasionally yield indeterminate results, exhibit suboptimal reproducibility, and carry a potential for misdiagnosis. This study aimed to propose a novel MMR IHC expression pattern and explore its clinical significance in EC. Methods Four hundred and seventy-five ECs were characterized using IHC and MSI testing. MMR/CK-pan dual staining confirmed the tumor cell identity of cells exhibiting scattered nuclear staining (SNS). Cases were stratified into four groups based on distinct MMR IHC expression patterns and compared for clinicopathological differences. Results Four hundred and seventy-five ECs were classified; 75% as mismatch repair-proficient (pMMR) group (intact expression of all 4 MMR proteins, ≥ 5% staining), 13% mismatch repair-deficient (dMMR) group (complete loss of expression of one or more MMR proteins), 2% subclonal group, and 10% as SNS group (< 5% staining). The dMMR group were associated with advanced stage, higher grade, presence of lymphovascular space invasion, and significant lymphocyte infiltration around tumor. The SNS group demonstrated aggressive biological behavior similar to, yet distinct from the dMMR group, exhibiting a higher incidence of cervical stromal invasion and lymph node metastasis. MSI testing confirmed that 62.9% of SNS cohort exhibited microsatellite instability-high (MSI-H) status. Different combinations of MMR IHC patterns may provide indicative clues for MSI status. Conclusions SNS represents an objectively identifiable phenomenon within MMR IHC expression patterns and should be recognized as a distinct MMR IHC expression category. The establishment of this pattern not only addresses unmet needs in clinical practice but also complements the existing College of American Pathologists (CAP) guidelines. Endometrial carcinoma Immunohistochemistry Scattered nuclear staining Mismatch repair protein Microsatellite instability Immunotherapy Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Endometrial cancer (EC) is one of the most common malignant tumors in the female reproductive system, which occurs mostly in perimenopausal and postmenopausal women 1 . Clinically, approximately 80% of EC patients present with tumors confined to the uterine corpus at initial diagnosis, correlating with early-stage disease and favorable prognoses 2 . However, patients with advanced, metastatic, or recurrent disease face significantly poorer prognoses and have limited effective therapeutic options available, remaining a major therapeutic challenge in gynecologic oncology. The 5-year survival rates starkly reflect this prognostic dichotomy: 91% for FIGO stage IA, 47% for stage III, and only 17% for stage IV disease 3 . Surgical intervention followed by adjuvant radiotherapy and/or chemotherapy remains the cornerstone of the management for patients with advanced and recurrent disease 2 . Accumulating clinical data highlights the efficacy and safety of immunotherapy with checkpoint inhibitors in various tumor types, with EC demonstrating comparable responsiveness particularly in mismatch repair-deficient (dMMR) subtypes 4 , 5 . Recently, the molecular classification of EC based on the Cancer Genome Atlas (TCGA) data has played a remarkable role in identifying prognostic and predictive factors, which are now influencing the selection of appropriate treatment approaches as well as the design of future therapeutic agents 6 . EC is divided into four molecular subtypes: microsatellite-instable/ hypermutated (dMMR/MSI-H), copy number high (CNH)/p53abn, copy number low (CNL)/no specific molecular profile (NSMP), and POLE mutated 7 – 9 . Mismatch repair protein (MMR) immunohistochemistry (IHC) is a universally adopted tool for patients with EC considered for immune checkpoint inhibitor therapy or screening for Lynch syndrome tumors 10 . In the era of rapid advancements in immunotherapy, accurate interpretation of MMR IHC results is critical. A positive reaction in any tumor cell nucleus is considered as intact expression (normal) when a positive reaction occurs in an internal control cell (such as a stromal cell, an inflammatory cell, or a nucleus of a non-tumor epithelial cell) 11 . However, in practice, IHC staining is sometimes not very clear with weak/equivocal expression, which can lead to indeterminate results and misinterpretation of findings. In this study, we evaluated MMR IHC slides of 475 patients with EC after surgery and found several unusual expression patterns, including scattered nuclear staining (SNS), subclonal staining, heterogeneous and non-specific staining of tumor cells (ie, dotlike para-nuclear staining, cell membrane or cytoplasmic staining). MMR/CK-pan dual staining confirmed the tumor cell identity of cells exhibiting SNS. According to the immunohistochemical expression profiles of MMR, the cases were stratified into four distinct categories: mismatch repair-proficient (pMMR) group, dMMR group, subclonal group, and SNS group. We compared the SNS group and the dMMR group, found that microsatellite instability (MSI) and microsatellite stability (MSS) testing by polymerase chain reaction (PCR) were present in both groups. Moreover, compared with the pMMR group, patients in the SNS group had more aggressive biological behaviors, such as cervical interstitial invasion was more likely to appear. It is imperative to establish a more standardized method for interpreting MMR IHC, including the creation of well-defined criteria for reporting SNS results. We believed that the SNS of MMR IHC is an objective fact and should be approved as an independent MMR IHC expression pattern. Materials and Methods Selection of Cases and Data Collection We retrospectively reviewed the data on MMR (MLH1, PMS2, MSH2, and MSH6) IHC results from Tianjin Medical University Cancer Institute and Hospital of 475 postoperative patients with EC between June 2021 and August 2023. The patients did not receive any adjuvant treatment before surgery. The postoperative pathology was confirmed as endometrioid adenocarcinoma in all patients. Any patient who underwent a hysterectomy and had case slides available for review, including the MMR protein IHC panel, was included in the study. SNS was defined as approximately 5 percent of tumor cells showing nuclear positivity with surrounding stroma serving as a positive internal control. ALL clinicopathologic data were collected from medical records. Tumor staging was determined according to the American Joint Committee on Cancer (8th edition) criteria. MMR IHC Evaluation Hematoxylin and eosin (HE) stained tissue sections and corresponding MMR-IHC protein were independently evaluated by two senior pathologists under the microscope, and IHC interpretation according to the College of American Pathologists (CAP) guidelines in which any positive reaction in the nuclei of tumor cells (assuming there is no problem with internal control staining) was considered intact expression. Ventana/Roche antibodies, including MLH1 (clone M1), MSH2 (clone G219-1129), MSH6 (clone SP93), and PMS2 (clone A16-4), were stained using Ventana’s automated staining system (Benchmark XT). In cases exhibiting SNS pattern, the samples were re-stained with an alternative antibody clone (MLH1, clone MX063; MSH2, clone MX061; MSH6, clone MX056; PMS2, clone MXR019) and the results were assessed. The pattern of SNS remained consistently observable in the corresponding cases when different clone numbers were employed. Double immunohistochemical staining with MMR/CK-pan Double immunohistochemical staining with MMR/CK-pan was performed using Roche BenchMark®Ultra. These 2 stains were chosen because the antibodies show staining limited to the cytoplasm and nucleus, respectively, avoiding interference with interpretation between the stains 12 , 13 . The nuclei of MMR positive cells were brown-yellow, and the cytoplasm of CK-pan positive cells were red. The cytoplasm of normal glandular epithelium was stained red and the nucleus was stained brown-yellow, while the nucleus of stromal cells (such as lymphocytes) was brown-yellow but the cytoplasm was not stained and can be used as a control. On the basis of successful control staining, for cancer cells with abnormal distribution of CK8/18 positive, brown-yellow nucleus staining was marked as positive, and no brown-yellow nucleus staining was marked as negative. The staining results were interpreted by two experienced pathologists. MSI testing MSI was analyzed by a PCR-based assay using fluorescently labeled primers to 5 DNA microsatellites (BAT-25, BAT-26, D2S123, D5S346, and D17S250) 14 . Normal and tumor allele patterns were compared for each marker. Tumors were classified as MSI-H if novel alleles were seen at ≥ 2 loci and microsatellite instability-low (MSI-L) if novel alleles were in only 1 locus 15 . Prior studies had demonstrated that MSS and MSI-L cases exhibit comparable clinicopathological characteristics, leading to their combined classification in molecular subtyping systems 16 , 17 . Statistical analysis All statistical analyses were performed using χ2 tests and Fisher exact tests in SPSS 22.0 (IBM, Chicago, IL, USA). P < 0.05 indicated statistical significance. Results Comparison of clinicopathological features between the dMMR group and pMMR group Of the 475 cases with IHC results, 356 (75%) were reported as intact expression of all 4 MMR proteins (≥ 5% staining), 61 (13%) had complete loss of expression of one or more MMR proteins, 11 (2%) were divided into subclone staining group, and 47 (10%) were described SNS (< 5% staining). A comparison of clinical-pathologic features in patients with intact versus loss of expression was shown in Table 1 . The results showed statistically significant differences in FIGO clinical stage, FIGO grade, lymphovascular space invasion and peritumor lymphocyte infiltration. Compared with the pMMR group, the dMMR group showed low-differentiated solid flakiness growth pattern, nucleolus were visible at high magnification, with high-grade nuclear features (Fig. 1). There were often significant lymphocyte infiltration around the tumor and vascular cancer thrombolus in the dMMR group, and FIGO clinical stages were mostly stage Ⅲ~Ⅳ. These results suggested that the clinical pathobiological behavior of EC in dMMR group was poor. Table 1 Comparison of Clinicopathological Characteristics Among Groups with Different Immunohistochemical Expression Patterns Variable dMMR group (n = 61) pMMR group (n = 356) P value SNS group (n = 47) dMMR group (n = 61) P value SNS group (n = 47) pMMR group (n = 356) P value SNS/MSI-H (n = 22) SNS/MSS + MSI-L (n = 13) P value Age 55 ± 7 54 ± 9 0.346 56 ± 7 55 ± 7 0.575 56 ± 7 54 ± 9 0.315 57 ± 8 55 ± 6 0.527 FIGO stage < 0.001* 0.866 < 0.001* 0.379 stageⅠ 38 300 27 38 27 300 11 9 stage Ⅱ 12 32 12 12 12 32 8 2 stage Ⅲ 10 19 8 10 8 19 3 2 stage Ⅳ 1 5 0 1 0 5 0 0 FIGO grade < 0.001* 0.78 < 0.001* 0.043* grade 1 23 224 15 23 15 224 4 6 grade 2 24 109 19 24 19 109 8 5 grade 3 14 23 13 14 13 23 10 2 Tumor invasion depth 0.155 0.502 0.755 0.198 intramucosal 3 43 4 3 4 43 0 2 superficial muscular layer 51 259 35 51 35 259 17 9 deep muscular layer 7 54 8 7 8 54 5 2 Lymphovascular space invasion 0.017* 0.743 0.007* 0.047* absence 38 278 29 38 29 278 11 11 focal 13 52 8 13 8 52 5 1 extensive 10 26 10 10 10 26 6 1 Cervical stromal involvement 0.126 0.631 0.039* 0.337 absence 55 339 41 55 41 339 20 10 presence 6 17 6 6 6 17 2 3 Peritumor infiltrating lymphocytes < 0.001* 0.205 0.999 NS 4 49 2 4 2 49 1 1 absence 53 295 40 53 40 295 18 11 presence 4 12 5 4 5 12 3 1 * P < 0.05; dMMR, mismatch repair-deficient; pMMR, mismatch repair-proficient; SNS, scattered nuclear staining; NS, not submitted; MSS, Microsatellite Stability; MSI-L, Microsatellite Instability-Low; MSI-H, Microsatellite Instability-High. The characteristics and significance of SNS group The SNS group comprised 47 cases. Using MMR/CK-pan IHC double staining, we confirmed that the positively stained cells were tumor cells. These cells exhibited large irregular nuclei with brown-yellow staining, and the surrounding cytoplasm showed a CK-positive red signal, confirming their tumor cell identity (Fig. 2). According to CAP guidelines, these cases should be classified into the pMMR group. However, we proceeded to compare the clinicopathological and morphological features between the SNS group and the dMMR group. The results showed that none of the clinicopathological features differed significantly between the two groups (Table 1 ), suggesting that their biological behaviors were similar. Furthermore, we compared the SNS group with the pMMR group and found that, in addition to sharing aggressive biological features with the dMMR group, the SNS group exhibited distinct differences in cervical stromal invasion and lymph node metastasis (Fig. 3). As shown in Table 1 , the SNS group was more likely to exhibit cervical stromal invasion ( p = 0.039) and lymph node metastasis ( p = 0.018). These findings suggest that the SNS group resembles the dMMR group but is not entirely identical. Therefore, regarding the interpretation of MMR IHC, we believe that SNS represents a distinct biological phenomenon and should be recognized as an independent interpretation pattern, rather than being classified into the pMMR group based on the binary classification (all-positive or all-negative) recommended in the guidelines. The correlation between the expression pattern of MMR IHC and MSI status In order to further explore the correlation between the expression pattern of MMR IHC and MSI status in EC, PCR analysis was performed on authorized patient samples (n = 307). Given the well-established relationship between pMMR, dMMR, and microsatellite status, we focused our analysis on the SNS expression pattern. Among the 35 cases with SNS, 22 (62.9%) were confirmed as MSI-H by PCR, while the remaining 13 (37.1%) were classified as MSS/MSI-L. A comparison of clinicopathological features between SNS patients with MSS/MSI-L and those with MSI-H was shown in Table 1 . The results showed statistically significant differences in FIGO grade and lymphovascular space invasion. Compared to patients with MSS/MSI-L, those with MSI-H had higher FIGO grades ( p = 0.043) and were more likely to exhibit lymphovascular space invasion ( p = 0.047). Collectively, these findings suggest that the SNS pattern is analogous to the dMMR pattern. This underscores the need for confirmatory PCR testing in this patient subgroup to ensure they are not overlooked for potential immunotherapy. The correspondence between different MMR-IHC expression profiles and MSI status in the SNS group We mapped the correspondence between MMR-IHC expression profiles and MSI status in the SNS group (Fig. 4). 22 (62.9%) were classified as MSI-H by PCR analysis. The majority of MSI-H cases exhibited concurrent SNS of MLH1 and PMS2 expression (14/22, 63.6%), with the remaining cases showing combined SNS of MSH2 and MSH6 (7/22, 31.8%) and isolated PMS2 SNS (1/22, 4.5%). Conversely, 13 cases (37.1%) were categorized as MSS/MSI-L, predominantly characterized by MLH1/PMS2 co-SNS (9/13, 69.2%), followed by isolated MSH6 SNS (4/13, 30.8%). Notably, concurrent SNS of MSH2 and MSH6 expression exhibited a high concordance with PCR-based MSI-H classification, making these patterns reliable immunohistochemical surrogates for predicting MSI-H status. In contrast, isolated MSH6 SNS strongly correlated with a MSS phenotype. These results further confirm that MSH2 serves as the dominant and indispensable subunit within the MSH2-MSH6 heterodimeric complex (MutSα). Among cases with concurrent SNS of MLH1 and PMS2, over half were confirmed as MSI-H by PCR, underscoring the necessity of PCR testing for such cases in clinical practice. Thus, in routine diagnostics, evaluation should extend beyond individual MMR proteins to include combinatorial expression patterns. In resource-constrained settings without access to PCR, an integrated assessment of co-SNS patterns (e.g., MSH2/MSH6) may offer practical predictive value for inferring microsatellite status. Discussion In our evaluation of 475 MMR IHC slides from EC cases, 356 (75%) showed intact expression of all MMR proteins, 61 (13%) showed loss of expression of one or more MMR proteins, 11 (2%) exhibited subclonal staining, and 47 (10%) were classified as SNS—defined by positive staining in less than 5% of tumor cells with weak to moderate intensity, in the presence of appropriately stained internal controls. MSI testing was performed on each IHC expression group to determine MSI status. In addition, MSI testing was performed on each IHC expression group to determine MSI status. By comparing clinicopathological differences between groups with different MMR IHC expression patterns, we found that the SNS group was similar to, but not identical to, the dMMR group. The PCR testing also confirmed that more than half of the SNS cases were indeed MSI-H. However, the current CAP guidelines for IHC interpretation failed to identify cases exhibiting this distinct pattern in our study. It is therefore necessary to establish a more standardized framework for evaluating MMR IHC staining, including well-defined criteria for reporting SNS. Our findings indicate that SNS represents a novel and independent pattern in MMR IHC interpretation. Incorporating SNS into future iterations of the CAP guidelines could significantly improve the accuracy and clinical utility of MMR testing, especially in diagnostically challenging cases. Based on MMR IHC expression patterns, the cases were classified into four groups: pMMR, dMMR, subclonal, and SNS. The clinicopathological features among these groups were subsequently compared. Similar to most reports in the literature 18 – 22 , MMR deficiency was associated with adverse prognostic factors. Patients in the dMMR group were more likely to have lymphovascular space invasion and advanced FIGO stage. These tumors were often poorly differentiated, exhibiting solid growth patterns and high-grade nuclear features rather than conventional glandular structures. They were also frequently accompanied by prominent lymphocyte infiltration. Moreover, we compared the clinicopathological features of the SNS group with those of the pMMR group and the dMMR group, respectively. Compared to the pMMR group, the SNS group exhibited aggressive biological behaviors similar to the dMMR group. However, it was not identical to the dMMR group. We found subtle differences, primarily in that the SNS group showed a greater propensity for cervical stromal invasion and a higher rate of lymph node metastasis. These findings support classifying SNS as a novel and independent MMR IHC expression pattern, distinct from both pMMR and dMMR. Significant advances have been made in understanding the pathological and molecular features of EC 23 . With the growing emphasis on molecular classification in EC, accurate and reproducible assays are critical for improving patient outcomes. However, some discordance between MMR IHC and PCR results is predictable. This can occur when certain mutations lead to dysfunctional proteins that retain epitopes detectable by standard IHC 24 – 26 . E. Stelloo et al. suggested that the majority of discordant cases involve the loss of MMR protein expression and a MSS or MSI-L phenotype, which can be explained by MLH1 promoter hypermethylation or MMR gene mutations 27 . Furthermore, interobserver variability among pathologists in interpreting indeterminate staining patterns represents another significant contributing factor 28 . Indeterminate staining can result from nontruncating or noncoding mutations that preserve the expression of a nonfunctional enzyme 29 .The findings by Venetia R et al. further support that indeterminate immunohistochemistry results warrant further investigation for possible underlying MMR germline mutations 11 .These findings are largely consistent with our results. We defined a staining pattern of weak-to-moderate intensity in fewer than 5% of tumor cells as SNS and subsequently stratified these SNS cases into MSI-H and MSS/MSI-L groups using PCR. Compared with the MSS/MSI-L group, we found that the MSI-H group had aggressive biological behavior similar to the dMMR group. The MSI-H group was more poorly differentiated histologically ( p = 0.043) and more prone to extensive vascular tumor thrombi ( p = 0.047) ( Table 1 ). These findings fundamentally challenge conventional immunohistochemical interpretation paradigms by demonstrating that SNS patterns carry equivalent diagnostic weight to complete nuclear loss. Establishing clear criteria for defining these cases can greatly mitigate discordant interpretations and interobserver variability among pathologists. Our analysis of MMR IHC expression patterns in relation to microsatellite status revealed several clinically relevant correlations. Notably, the distribution of specific SNS patterns differed markedly between the MSI-H and MSS/MSI-L groups. Although MLH1/PMS2 co-localized SNS was frequently observed in both cohorts, its associated patterns differed. A striking finding was that all cases showing concurrent SNS for both MSH2 and MSH6 exhibited MSI-H (7/7, 100%), indicating that this staining pattern may strongly predict microsatellite instability and could help identify cases for confirmatory PCR testing. In contrast, every case with isolated MSH6 SNS was MSS (4/4, 100%), suggesting that MSH2 status may be determinative—preserved MSH2 function appears to maintain genomic stability even when MSH6 staining is abnormal. This finding highlights the central role of MSH2 in regulating the MutSα heterodimer and influencing microsatellite phenotypes 30 . In resource-limited primary care settings, these distinctive staining patterns may provide a practical diagnostic tool for gynecologists to identify high-risk patients who require intensified postoperative follow-up and Lynch syndrome screening. Emerging reports have documented subclonal expression patterns, with our study identifying 11 such cases demonstrating intratumoral heterogeneity 9 , 27 , 31 , 32 . Subsequent PCR analysis of spatially distinct MMR-IHC expression zones within these tumors confirmed the coexistence of differential microsatellite states. Moreover, previous studies have indicated that heterogeneous staining patterns—including cytoplasmic, nucleolar, and membranous staining—are inevitable in MMR IHC evaluation 9 , 33 . These variations may be associated with technical factors such as inadequate tissue fixation or degradation in archived paraffin blocks 11 , 34 , 35 . We also observed this phenomenon in our study. Heterogeneous staining was identified in 11 cases in our cohort, most frequently affecting PMS2, probably due to its greater sensitivity to tissue hypoxia and more demanding requirements for optimal fixation 35 . Through replacement of paraffin blocks, repetition of IHC staining, and optimization of the staining protocol, these cases were confirmed to show a complete lack of nuclear staining. Therefore, strict adherence to the IHC staining protocol and the consistent use of positive controls are essential for accurate interpretation of PMS2 staining results. Certainly, our study also has some limitations. The relatively small number of cases in the SNS group may limit the generalizability of the findings. Future prospective, multi-center studies with larger cohorts are warranted to validate our proposed SNS criteria. Furthermore, functional experiments are needed to elucidate the precise mechanism by which these mutant proteins influence tumor biology. Long-term follow-up studies are needed to determine the prognostic and predictive significance of the SNS pattern in EC and other cancers, including response to therapies such as immunotherapy, which is often effective in dMMR tumors. Currently, immunotherapy is evolving in endometrial cancer 36 , 37 . Haider et al. emphasized the importance of categorizing EC into two immunologically distinct subtypes: MSI-H and MSS. They also called for future clinical trials and treatment designs to take these immunological subtypes into account in order to optimize therapeutic outcomes 6 . It is important to accurately distinguish the state of the mismatch repair system. Notably, all cases in our study were postoperatively confirmed as endometrioid adenocarcinoma, predominantly of low grade (grade 1 or 2) and thus would represent the majority of EC cases diagnosed. Conclusion To our knowledge, the concept of the scattered staining pattern in MMR IHC has not been formally defined in the literature. Here, we present the first study to define and validate this SNS pattern, establishing it as a distinct, reproducible category in MMR IHC interpretation. The identification of the SNS pattern addresses an unmet need in clinical practice and provides a valuable complement to existing CAP guidelines. Abbreviations IHC Immunohistochemistry MMR Mismatch repair protein MSI Microsatellite instability EC Endometrial carcinoma SNS Scattered nuclear staining pMMR Mismatch repair-proficient dMMR Mismatch repair-deficient MSI-H Microsatellite instability-high CAP College of American Pathologists TCGA the Cancer Genome Atlas dMMR/MSI-H Microsatellite-instable/ hypermutated CNH Copy number high CNL Copy number low NSMP No specific molecular profile MSS Microsatellite stability PCR Polymerase chain reaction Declarations Acknowledgements We thank all the patients and researchers participated in this study. Authors’ Contributions Qiujuan Huang, Wenxin Liu, Wenfeng Cao: Conceptualization. Yutian Wang, Bo Yang, Lisha Qi, Lin Sun, Ye Luo: Methodology. Qing Li, Jing Luan, Qianru Guo, Manlin Yang: Data curation. Qiujuan Huang: Writing- Original draft preparation. Yuhong Guo, Yalei Wang: Visualization, Investigation. Lingmei Li: Supervision. Lu Cao: Software, Validation. Qiujuan Huang: Writing- Reviewing and Editing. All authors read and approved the final manuscript. Funding This work was funded by the Special Fund for pharmacy, examination, and imaging of Tianjin Medical University Cancer Institute and Hospital (Y2309) and funded by Tianjin Key Medical Discipline Construction Project (Grant No.TJYXZDXK-3-016C). Data availability The data are available from the corresponding author upon reasonable request. Ethics approval and consent to participate The study was approved by the Research Ethics Committee of Tianjin Medical University Cancer Institute & Hospital (Number: bc2022174). Written informed consent was waived by the ethics committee. This study was conducted by the Declaration of Helsinki. Consent for publication Not applicable. Competing interests The authors declare no competing interests. References Sung H, Ferlay J, Siegel RL, et al. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J Clin 2021;71:209-249. Urick ME, Bell DW. Clinical actionability of molecular targets in endometrial cancer. Nat Rev Cancer 2019;19:510-521. Colombo N, Creutzberg C, Amant F, et al. ESMO-ESGO-ESTRO Consensus Conference on Endometrial Cancer: diagnosis, treatment and follow-up. Ann Oncol 2016;27:16-41. Marabelle A, Le DT, Ascierto PA, et al. Efficacy of Pembrolizumab in Patients With Noncolorectal High Microsatellite Instability/Mismatch Repair-Deficient Cancer: Results From the Phase II KEYNOTE-158 Study. J Clin Oncol 2020;38:1-10. Oaknin A, Tinker AV, Gilbert L, et al. Clinical Activity and Safety of the Anti-Programmed Death 1 Monoclonal Antibody Dostarlimab for Patients With Recurrent or Advanced Mismatch Repair-Deficient Endometrial Cancer: A Nonrandomized Phase 1 Clinical Trial. JAMA Oncol 2020;6:1766-1772. Mahdi H, Chelariu-Raicu A, Slomovitz BM. Immunotherapy in endometrial cancer. Int J Gynecol Cancer 2023;33:351-357. Karpel HC, Slomovitz B, Coleman RL, et al. Treatment options for molecular subtypes of endometrial cancer in 2023. Curr Opin Obstet Gynecol 2023;35:270-278. Di Dio C, Bogani G, Di Donato V, et al. The role of immunotherapy in advanced and recurrent MMR deficient and proficient endometrial carcinoma. Gynecol Oncol 2023;169:27-33. Pai RK, Plesec TP, Abdul-Karim FW, et al. Abrupt loss of MLH1 and PMS2 expression in endometrial carcinoma: molecular and morphologic analysis of 6 cases. Am J Surg Pathol 2015;39:993-9. Chen W, Pearlman R, Hampel H, et al. MSH6 immunohistochemical heterogeneity in colorectal cancer: comparative sequencing from different tumor areas. Human Pathology 2020;96:104-111. Sarode VR, Robinson L. Screening for Lynch Syndrome by Immunohistochemistry of Mismatch Repair Proteins: Significance of Indeterminate Result and Correlation With Mutational Studies. Archives of Pathology & Laboratory Medicine 2019;143:1225-1233. Bhardwaj A, Marsh WL, Jr., Nash JW, et al. Double immunohistochemical staining with MUC4/p53 is useful in the distinction of pancreatic adenocarcinoma from chronic pancreatitis: a tissue microarray-based study. Arch Pathol Lab Med 2007;131:556-62. Annese T, Errede M, De Giorgis M, et al. Double Immunohistochemical Staining on Formalin-Fixed Paraffin-Embedded Tissue Samples to Study Vascular Co-option. Tumor Angiogenesis Assays, 2023:101-116. Goodfellow PJ, Billingsley CC, Lankes HA, et al. Combined Microsatellite Instability, MLH1 Methylation Analysis, and Immunohistochemistry for Lynch Syndrome Screening in Endometrial Cancers From GOG210: An NRG Oncology and Gynecologic Oncology Group Study. J Clin Oncol 2015;33:4301-8. Watkins JC, Nucci MR, Ritterhouse LL, et al. Unusual Mismatch Repair Immunohistochemical Patterns in Endometrial Carcinoma. Am J Surg Pathol 2016;40:909-16. Riedinger CJ, Esnakula A, Haight PJ, et al. Characterization of mismatch-repair/microsatellite instability-discordant endometrial cancers. Cancer 2024;130:385-399. Kim H, Jen J, Vogelstein B, et al. Clinical and pathological characteristics of sporadic colorectal carcinomas with DNA replication errors in microsatellite sequences. Am J Pathol 1994;145:148-56. Carr C, Son J, Yao M, et al. Clinicopathologic characteristics and outcomes of endometrial Cancer patients with mismatch repair deficiency in the era of universal Lynch syndrome screening. Gynecol Oncol 2020;159:712-720. Cosgrove CM, Cohn DE, Hampel H, et al. Epigenetic silencing of MLH1 in endometrial cancers is associated with larger tumor volume, increased rate of lymph node positivity and reduced recurrence-free survival. Gynecol Oncol 2017;146:588-595. Backes FJ, Haag J, Cosgrove CM, et al. Mismatch repair deficiency identifies patients with high-intermediate-risk (HIR) endometrioid endometrial cancer at the highest risk of recurrence: A prognostic biomarker. Cancer 2019;125:398-405. McMeekin DS, Tritchler DL, Cohn DE, et al. Clinicopathologic Significance of Mismatch Repair Defects in Endometrial Cancer: An NRG Oncology/Gynecologic Oncology Group Study. J Clin Oncol 2016;34:3062-8. Nagle CM, O'Mara TA, Tan Y, et al. Endometrial cancer risk and survival by tumor MMR status. J Gynecol Oncol 2018;29:e39. Turashvili G, Hanley K. Practical Updates and Diagnostic Challenges in Endometrial Carcinoma. Archives of Pathology & Laboratory Medicine 2023;148:78-98. Shia J, Holck S, Depetris G, et al. Lynch syndrome-associated neoplasms: a discussion on histopathology and immunohistochemistry. Fam Cancer 2013;12:241-60. Mangold E, Pagenstecher C, Friedl W, et al. Tumours from MSH2 mutation carriers show loss of MSH2 expression but many tumours from MLH1 mutation carriers exhibit weak positive MLH1 staining. J Pathol 2005;207:385-95. Dudley B, Brand RE, Thull D, et al. Germline MLH1 Mutations Are Frequently Identified in Lynch Syndrome Patients With Colorectal and Endometrial Carcinoma Demonstrating Isolated Loss of PMS2 Immunohistochemical Expression. Am J Surg Pathol 2015;39:1114-20. Stelloo E, Jansen AML, Osse EM, et al. Practical guidance for mismatch repair-deficiency testing in endometrial cancer. Ann Oncol 2017;28:96-102. Klarskov L, Ladelund S, Holck S, et al. Interobserver variability in the evaluation of mismatch repair protein immunostaining. Hum Pathol 2010;41:1387-96. Shia J. Immunohistochemistry versus microsatellite instability testing for screening colorectal cancer patients at risk for hereditary nonpolyposis colorectal cancer syndrome. Part I. The utility of immunohistochemistry. J Mol Diagn 2008;10:293-300. Haron NH, Mohamad Hanif EA, Abdul Manaf MR, et al. Microsatellite Instability and Altered Expressions of MLH1 and MSH2 in Gastric Cancer. Asian Pac J Cancer Prev 2019;20:509-517. Scheiderer A, Riedinger C, Kimball K, et al. Reporting Subclonal Immunohistochemical Staining of Mismatch Repair Proteins in Endometrial Carcinoma in the Times of Ever-Changing Guidelines. Archives of Pathology & Laboratory Medicine 2022;146:1114-1121. Casey L, Singh N. POLE, MMR, and MSI Testing in Endometrial Cancer: Proceedings of the ISGyP Companion Society Session at the USCAP 2020 Annual Meeting. International Journal of Gynecological Pathology 2021;40:5-16. Joost P, Veurink N, Holck S, et al. Heterogenous mismatch-repair status in colorectal cancer. Diagn Pathol 2014;9:126. Barrow E, Jagger E, Brierley J, et al. Semiquantitative assessment of immunohistochemistry for mismatch repair proteins in Lynch syndrome. Histopathology 2010;56:331-344. Chang CL, Marra G, Chauhan DP, et al. Oxidative stress inactivates the human DNA mismatch repair system. Am J Physiol Cell Physiol 2002;283:C148-54. Eskander RN, Sill MW, Beffa L, et al. Pembrolizumab plus Chemotherapy in Advanced Endometrial Cancer. N Engl J Med 2023;388:2159-2170. Mirza MR, Chase DM, Slomovitz BM, et al. Dostarlimab for Primary Advanced or Recurrent Endometrial Cancer. N Engl J Med 2023;388:2145-2158. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Review Version 1 posted Editorial decision: Revision requested 31 Dec, 2025 Reviews received at journal 22 Dec, 2025 Reviews received at journal 09 Dec, 2025 Reviewers agreed at journal 01 Dec, 2025 Reviewers agreed at journal 18 Nov, 2025 Reviewers invited by journal 18 Nov, 2025 Editor assigned by journal 13 Nov, 2025 Editor invited by journal 13 Nov, 2025 Submission checks completed at journal 12 Nov, 2025 First submitted to journal 12 Nov, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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2","display":"","copyAsset":false,"role":"figure","size":10808524,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version\u003c/p\u003e","description":"","filename":"Fig.2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8078986/v1/15416c77b947275a833f778d.jpg"},{"id":97136477,"identity":"dc8f25ad-03e7-4bae-97c0-45dfdb35d2ba","added_by":"auto","created_at":"2025-12-01 09:56:37","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":17621138,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version\u003c/p\u003e","description":"","filename":"Fig.3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8078986/v1/ebd7e60e91301a43942d9771.jpg"},{"id":96968945,"identity":"d82bffee-8616-40ba-afb9-f84418755df9","added_by":"auto","created_at":"2025-11-28 07:07:21","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":778660,"visible":true,"origin":"","legend":"\u003cp\u003eLegend not included with this version\u003c/p\u003e","description":"","filename":"Fig.4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8078986/v1/fb62d0617c5a599227d8a763.jpg"},{"id":97249319,"identity":"9859e638-342d-46e3-87df-428863c4d5e7","added_by":"auto","created_at":"2025-12-02 13:12:10","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":48637917,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8078986/v1/ddab3eaf-1b6f-4d74-a91e-bedaede0540d.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Scattered Nuclear Staining: A Novel Immunohistochemical Expression Pattern of Mismatch Repair Proteins and Its Significance in Endometrial Carcinoma","fulltext":[{"header":"Introduction","content":"\u003cp\u003eEndometrial cancer (EC) is one of the most common malignant tumors in the female reproductive system, which occurs mostly in perimenopausal and postmenopausal women\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. Clinically, approximately 80% of EC patients present with tumors confined to the uterine corpus at initial diagnosis, correlating with early-stage disease and favorable prognoses\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. However, patients with advanced, metastatic, or recurrent disease face significantly poorer prognoses and have limited effective therapeutic options available, remaining a major therapeutic challenge in gynecologic oncology. The 5-year survival rates starkly reflect this prognostic dichotomy: 91% for FIGO stage IA, 47% for stage III, and only 17% for stage IV disease\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. Surgical intervention followed by adjuvant radiotherapy and/or chemotherapy remains the cornerstone of the management for patients with advanced and recurrent disease\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. Accumulating clinical data highlights the efficacy and safety of immunotherapy with checkpoint inhibitors in various tumor types, with EC demonstrating comparable responsiveness particularly in mismatch repair-deficient (dMMR) subtypes\u003csup\u003e\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eRecently, the molecular classification of EC based on the Cancer Genome Atlas (TCGA) data has played a remarkable role in identifying prognostic and predictive factors, which are now influencing the selection of appropriate treatment approaches as well as the design of future therapeutic agents\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. EC is divided into four molecular subtypes: microsatellite-instable/ hypermutated (dMMR/MSI-H), copy number high (CNH)/p53abn, copy number low (CNL)/no specific molecular profile (NSMP), and POLE mutated\u003csup\u003e\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. Mismatch repair protein (MMR) immunohistochemistry (IHC) is a universally adopted tool for patients with EC considered for immune checkpoint inhibitor therapy or screening for Lynch syndrome tumors\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. In the era of rapid advancements in immunotherapy, accurate interpretation of MMR IHC results is critical. A positive reaction in any tumor cell nucleus is considered as intact expression (normal) when a positive reaction occurs in an internal control cell (such as a stromal cell, an inflammatory cell, or a nucleus of a non-tumor epithelial cell)\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. However, in practice, IHC staining is sometimes not very clear with weak/equivocal expression, which can lead to indeterminate results and misinterpretation of findings.\u003c/p\u003e\u003cp\u003eIn this study, we evaluated MMR IHC slides of 475 patients with EC after surgery and found several unusual expression patterns, including scattered nuclear staining (SNS), subclonal staining, heterogeneous and non-specific staining of tumor cells (ie, dotlike para-nuclear staining, cell membrane or cytoplasmic staining). MMR/CK-pan dual staining confirmed the tumor cell identity of cells exhibiting SNS. According to the immunohistochemical expression profiles of MMR, the cases were stratified into four distinct categories: mismatch repair-proficient (pMMR) group, dMMR group, subclonal group, and SNS group. We compared the SNS group and the dMMR group, found that microsatellite instability (MSI) and microsatellite stability (MSS) testing by polymerase chain reaction (PCR) were present in both groups. Moreover, compared with the pMMR group, patients in the SNS group had more aggressive biological behaviors, such as cervical interstitial invasion was more likely to appear. It is imperative to establish a more standardized method for interpreting MMR IHC, including the creation of well-defined criteria for reporting SNS results. We believed that the SNS of MMR IHC is an objective fact and should be approved as an independent MMR IHC expression pattern.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eSelection of Cases and Data Collection\u003c/h2\u003e\u003cp\u003e We retrospectively reviewed the data on MMR (MLH1, PMS2, MSH2, and MSH6) IHC results from Tianjin Medical University Cancer Institute and Hospital of 475 postoperative patients with EC between June 2021 and August 2023. The patients did not receive any adjuvant treatment before surgery. The postoperative pathology was confirmed as endometrioid adenocarcinoma in all patients. Any patient who underwent a hysterectomy and had case slides available for review, including the MMR protein IHC panel, was included in the study. SNS was defined as approximately 5 percent of tumor cells showing nuclear positivity with surrounding stroma serving as a positive internal control. ALL clinicopathologic data were collected from medical records. Tumor staging was determined according to the American Joint Committee on Cancer (8th edition) criteria.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eMMR IHC Evaluation\u003c/h3\u003e\n\u003cp\u003e Hematoxylin and eosin (HE) stained tissue sections and corresponding MMR-IHC protein were independently evaluated by two senior pathologists under the microscope, and IHC interpretation according to the College of American Pathologists (CAP) guidelines in which any positive reaction in the nuclei of tumor cells (assuming there is no problem with internal control staining) was considered intact expression. Ventana/Roche antibodies, including MLH1 (clone M1), MSH2 (clone G219-1129), MSH6 (clone SP93), and PMS2 (clone A16-4), were stained using Ventana\u0026rsquo;s automated staining system (Benchmark XT). In cases exhibiting SNS pattern, the samples were re-stained with an alternative antibody clone (MLH1, clone MX063; MSH2, clone MX061; MSH6, clone MX056; PMS2, clone MXR019) and the results were assessed. The pattern of SNS remained consistently observable in the corresponding cases when different clone numbers were employed. \u003cb\u003eDouble immunohistochemical staining with MMR/CK-pan\u003c/b\u003e\u003c/p\u003e\u003cp\u003eDouble immunohistochemical staining with MMR/CK-pan was performed using Roche BenchMark\u0026reg;Ultra. These 2 stains were chosen because the antibodies show staining limited to the cytoplasm and nucleus, respectively, avoiding interference with interpretation between the stains\u003csup\u003e\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. The nuclei of MMR positive cells were brown-yellow, and the cytoplasm of CK-pan positive cells were red. The cytoplasm of normal glandular epithelium was stained red and the nucleus was stained brown-yellow, while the nucleus of stromal cells (such as lymphocytes) was brown-yellow but the cytoplasm was not stained and can be used as a control. On the basis of successful control staining, for cancer cells with abnormal distribution of CK8/18 positive, brown-yellow nucleus staining was marked as positive, and no brown-yellow nucleus staining was marked as negative. The staining results were interpreted by two experienced pathologists.\u003c/p\u003e\n\u003ch3\u003eMSI testing\u003c/h3\u003e\n\u003cp\u003eMSI was analyzed by a PCR-based assay using fluorescently labeled primers to 5 DNA microsatellites (BAT-25, BAT-26, D2S123, D5S346, and D17S250)\u003csup\u003e\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. Normal and tumor allele patterns were compared for each marker. Tumors were classified as MSI-H if novel alleles were seen at \u0026ge;\u0026thinsp;2 loci and microsatellite instability-low (MSI-L) if novel alleles were in only 1 locus\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e. Prior studies had demonstrated that MSS and MSI-L cases exhibit comparable clinicopathological characteristics, leading to their combined classification in molecular subtyping systems\u003csup\u003e\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eAll statistical analyses were performed using χ2 tests and Fisher exact tests in SPSS 22.0 (IBM, Chicago, IL, USA). \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 indicated statistical significance.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eComparison of clinicopathological features between the dMMR group and pMMR group\u003c/h2\u003e\u003cp\u003eOf the 475 cases with IHC results, 356 (75%) were reported as intact expression of all 4 MMR proteins (\u0026ge;\u0026thinsp;5% staining), 61 (13%) had complete loss of expression of one or more MMR proteins, 11 (2%) were divided into subclone staining group, and 47 (10%) were described SNS (\u0026lt;\u0026thinsp;5% staining). A comparison of clinical-pathologic features in patients with intact versus loss of expression was shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The results showed statistically significant differences in FIGO clinical stage, FIGO grade, lymphovascular space invasion and peritumor lymphocyte infiltration. Compared with the pMMR group, the dMMR group showed low-differentiated solid flakiness growth pattern, nucleolus were visible at high magnification, with high-grade nuclear features (Fig.\u0026nbsp;1). There were often significant lymphocyte infiltration around the tumor and vascular cancer thrombolus in the dMMR group, and FIGO clinical stages were mostly stage Ⅲ~Ⅳ. These results suggested that the clinical pathobiological behavior of EC in dMMR group was poor.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparison of Clinicopathological Characteristics Among Groups with Different Immunohistochemical Expression Patterns\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"13\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c11\" colnum=\"11\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c12\" colnum=\"12\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c13\" colnum=\"13\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eVariable\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003edMMR group\u003c/p\u003e\u003cp\u003e(n\u0026thinsp;=\u0026thinsp;61)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003epMMR group (n\u0026thinsp;=\u0026thinsp;356)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eSNS group (n\u0026thinsp;=\u0026thinsp;47)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003edMMR group (n\u0026thinsp;=\u0026thinsp;61)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eSNS group (n\u0026thinsp;=\u0026thinsp;47)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003epMMR group (n\u0026thinsp;=\u0026thinsp;356)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c11\"\u003e\u003cp\u003eSNS/MSI-H (n\u0026thinsp;=\u0026thinsp;22)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c12\"\u003e\u003cp\u003eSNS/MSS\u0026thinsp;+\u0026thinsp;MSI-L (n\u0026thinsp;=\u0026thinsp;13)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c13\"\u003e\u003cp\u003e\u003cem\u003eP\u003c/em\u003e value\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAge\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e55\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e54\u0026thinsp;\u0026plusmn;\u0026thinsp;9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.346\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e56\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e55\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.575\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e56\u0026thinsp;\u0026plusmn;\u0026thinsp;7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e54\u0026thinsp;\u0026plusmn;\u0026thinsp;9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e0.315\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e57\u0026thinsp;\u0026plusmn;\u0026thinsp;8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" 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colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e0.379\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003estageⅠ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e300\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e27\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e38\u003c/p\u003e\u003c/td\u003e\u003ctd 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colname=\"c5\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e32\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003estage Ⅲ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" 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Ⅳ\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eFIGO grade\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.78\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u003cb\u003e0.043*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003egrade 1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e224\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e224\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003egrade 2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e109\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e24\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e109\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003egrade 3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e14\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eTumor invasion depth\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.155\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.502\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e0.755\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e0.198\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eintramucosal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e43\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003esuperficial muscular layer\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e259\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e51\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e35\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e259\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003edeep muscular layer\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLymphovascular space invasion\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e0.017*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.743\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e\u003cb\u003e0.007*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u003cb\u003e0.047*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eabsence\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e278\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e29\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e38\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e29\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e278\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003efocal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e52\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eextensive\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCervical stromal involvement\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.126\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.631\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e\u003cb\u003e0.039*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e0.337\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eabsence\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e339\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e55\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e41\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e339\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e20\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003epresence\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e17\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003ePeritumor infiltrating lymphocytes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.205\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e\u003cb\u003e\u0026lt;\u0026thinsp;0.001*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e0.817\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003elittle\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e323\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e323\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003emedium\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e23\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003erich\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e15\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e19\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e21\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLymph node metastasis\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e0.136\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e\u003cp\u003e0.699\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e\u003cp\u003e\u003cb\u003e0.018*\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e\u003cp\u003e\u0026gt;\u0026thinsp;0.999\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eNS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e49\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eabsence\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e295\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e53\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e40\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e295\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e18\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003epresence\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e\u003ctd align=\"left\" colname=\"c11\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c12\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"13\"\u003e*\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05; dMMR, mismatch repair-deficient; pMMR, mismatch repair-proficient; SNS, scattered nuclear staining; NS, not submitted; MSS, Microsatellite Stability; MSI-L, Microsatellite Instability-Low; MSI-H, Microsatellite Instability-High.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eThe characteristics and significance of SNS group\u003c/h3\u003e\n\u003cp\u003eThe SNS group comprised 47 cases. Using MMR/CK-pan IHC double staining, we confirmed that the positively stained cells were tumor cells. These cells exhibited large irregular nuclei with brown-yellow staining, and the surrounding cytoplasm showed a CK-positive red signal, confirming their tumor cell identity (Fig.\u0026nbsp;2). According to CAP guidelines, these cases should be classified into the pMMR group. However, we proceeded to compare the clinicopathological and morphological features between the SNS group and the dMMR group. The results showed that none of the clinicopathological features differed significantly between the two groups (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e), suggesting that their biological behaviors were similar. Furthermore, we compared the SNS group with the pMMR group and found that, in addition to sharing aggressive biological features with the dMMR group, the SNS group exhibited distinct differences in cervical stromal invasion and lymph node metastasis (Fig.\u0026nbsp;3). As shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, the SNS group was more likely to exhibit cervical stromal invasion (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.039) and lymph node metastasis (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.018). These findings suggest that the SNS group resembles the dMMR group but is not entirely identical. Therefore, regarding the interpretation of MMR IHC, we believe that SNS represents a distinct biological phenomenon and should be recognized as an independent interpretation pattern, rather than being classified into the pMMR group based on the binary classification (all-positive or all-negative) recommended in the guidelines.\u003c/p\u003e\n\u003ch3\u003eThe correlation between the expression pattern of MMR IHC and MSI status\u003c/h3\u003e\n\u003cp\u003eIn order to further explore the correlation between the expression pattern of MMR IHC and MSI status in EC, PCR analysis was performed on authorized patient samples (n\u0026thinsp;=\u0026thinsp;307). Given the well-established relationship between pMMR, dMMR, and microsatellite status, we focused our analysis on the SNS expression pattern. Among the 35 cases with SNS, 22 (62.9%) were confirmed as MSI-H by PCR, while the remaining 13 (37.1%) were classified as MSS/MSI-L. A comparison of clinicopathological features between SNS patients with MSS/MSI-L and those with MSI-H was shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. The results showed statistically significant differences in FIGO grade and lymphovascular space invasion. Compared to patients with MSS/MSI-L, those with MSI-H had higher FIGO grades (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.043) and were more likely to exhibit lymphovascular space invasion (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.047). Collectively, these findings suggest that the SNS pattern is analogous to the dMMR pattern. This underscores the need for confirmatory PCR testing in this patient subgroup to ensure they are not overlooked for potential immunotherapy.\u003c/p\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003eThe correspondence between different MMR-IHC expression profiles and MSI status in the SNS group\u003c/h2\u003e\u003cp\u003eWe mapped the correspondence between MMR-IHC expression profiles and MSI status in the SNS group (Fig.\u0026nbsp;4). 22 (62.9%) were classified as MSI-H by PCR analysis. The majority of MSI-H cases exhibited concurrent SNS of MLH1 and PMS2 expression (14/22, 63.6%), with the remaining cases showing combined SNS of MSH2 and MSH6 (7/22, 31.8%) and isolated PMS2 SNS (1/22, 4.5%). Conversely, 13 cases (37.1%) were categorized as MSS/MSI-L, predominantly characterized by MLH1/PMS2 co-SNS (9/13, 69.2%), followed by isolated MSH6 SNS (4/13, 30.8%). Notably, concurrent SNS of MSH2 and MSH6 expression exhibited a high concordance with PCR-based MSI-H classification, making these patterns reliable immunohistochemical surrogates for predicting MSI-H status. In contrast, isolated MSH6 SNS strongly correlated with a MSS phenotype. These results further confirm that MSH2 serves as the dominant and indispensable subunit within the MSH2-MSH6 heterodimeric complex (MutSα). Among cases with concurrent SNS of MLH1 and PMS2, over half were confirmed as MSI-H by PCR, underscoring the necessity of PCR testing for such cases in clinical practice. Thus, in routine diagnostics, evaluation should extend beyond individual MMR proteins to include combinatorial expression patterns. In resource-constrained settings without access to PCR, an integrated assessment of co-SNS patterns (e.g., MSH2/MSH6) may offer practical predictive value for inferring microsatellite status.\u003c/p\u003e\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eIn our evaluation of 475 MMR IHC slides from EC cases, 356 (75%) showed intact expression of all MMR proteins, 61 (13%) showed loss of expression of one or more MMR proteins, 11 (2%) exhibited subclonal staining, and 47 (10%) were classified as SNS\u0026mdash;defined by positive staining in less than 5% of tumor cells with weak to moderate intensity, in the presence of appropriately stained internal controls. MSI testing was performed on each IHC expression group to determine MSI status. In addition, MSI testing was performed on each IHC expression group to determine MSI status. By comparing clinicopathological differences between groups with different MMR IHC expression patterns, we found that the SNS group was similar to, but not identical to, the dMMR group. The PCR testing also confirmed that more than half of the SNS cases were indeed MSI-H. However, the current CAP guidelines for IHC interpretation failed to identify cases exhibiting this distinct pattern in our study. It is therefore necessary to establish a more standardized framework for evaluating MMR IHC staining, including well-defined criteria for reporting SNS. Our findings indicate that SNS represents a novel and independent pattern in MMR IHC interpretation. Incorporating SNS into future iterations of the CAP guidelines could significantly improve the accuracy and clinical utility of MMR testing, especially in diagnostically challenging cases.\u003c/p\u003e\u003cp\u003eBased on MMR IHC expression patterns, the cases were classified into four groups: pMMR, dMMR, subclonal, and SNS. The clinicopathological features among these groups were subsequently compared. Similar to most reports in the literature\u003csup\u003e\u003cspan additionalcitationids=\"CR19 CR20 CR21\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e, MMR deficiency was associated with adverse prognostic factors. Patients in the dMMR group were more likely to have lymphovascular space invasion and advanced FIGO stage. These tumors were often poorly differentiated, exhibiting solid growth patterns and high-grade nuclear features rather than conventional glandular structures. They were also frequently accompanied by prominent lymphocyte infiltration. Moreover, we compared the clinicopathological features of the SNS group with those of the pMMR group and the dMMR group, respectively. Compared to the pMMR group, the SNS group exhibited aggressive biological behaviors similar to the dMMR group. However, it was not identical to the dMMR group. We found subtle differences, primarily in that the SNS group showed a greater propensity for cervical stromal invasion and a higher rate of lymph node metastasis. These findings support classifying SNS as a novel and independent MMR IHC expression pattern, distinct from both pMMR and dMMR.\u003c/p\u003e\u003cp\u003eSignificant advances have been made in understanding the pathological and molecular features of EC\u003csup\u003e23\u003c/sup\u003e. With the growing emphasis on molecular classification in EC, accurate and reproducible assays are critical for improving patient outcomes. However, some discordance between MMR IHC and PCR results is predictable. This can occur when certain mutations lead to dysfunctional proteins that retain epitopes detectable by standard IHC\u003csup\u003e\u003cspan additionalcitationids=\"CR25\" citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. E. Stelloo et al. suggested that the majority of discordant cases involve the loss of MMR protein expression and a MSS or MSI-L phenotype, which can be explained by MLH1 promoter hypermethylation or MMR gene mutations\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. Furthermore, interobserver variability among pathologists in interpreting indeterminate staining patterns represents another significant contributing factor\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e. Indeterminate staining can result from nontruncating or noncoding mutations that preserve the expression of a nonfunctional enzyme\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e.The findings by Venetia R et al. further support that indeterminate immunohistochemistry results warrant further investigation for possible underlying MMR germline mutations\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e.These findings are largely consistent with our results. We defined a staining pattern of weak-to-moderate intensity in fewer than 5% of tumor cells as SNS and subsequently stratified these SNS cases into MSI-H and MSS/MSI-L groups using PCR. Compared with the MSS/MSI-L group, we found that the MSI-H group had aggressive biological behavior similar to the dMMR group. The MSI-H group was more poorly differentiated histologically (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.043) and more prone to extensive vascular tumor thrombi (\u003cem\u003ep\u003c/em\u003e\u0026thinsp;=\u0026thinsp;0.047) ( Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). These findings fundamentally challenge conventional immunohistochemical interpretation paradigms by demonstrating that SNS patterns carry equivalent diagnostic weight to complete nuclear loss. Establishing clear criteria for defining these cases can greatly mitigate discordant interpretations and interobserver variability among pathologists.\u003c/p\u003e\u003cp\u003eOur analysis of MMR IHC expression patterns in relation to microsatellite status revealed several clinically relevant correlations. Notably, the distribution of specific SNS patterns differed markedly between the MSI-H and MSS/MSI-L groups. Although MLH1/PMS2 co-localized SNS was frequently observed in both cohorts, its associated patterns differed. A striking finding was that all cases showing concurrent SNS for both MSH2 and MSH6 exhibited MSI-H (7/7, 100%), indicating that this staining pattern may strongly predict microsatellite instability and could help identify cases for confirmatory PCR testing. In contrast, every case with isolated MSH6 SNS was MSS (4/4, 100%), suggesting that MSH2 status may be determinative\u0026mdash;preserved MSH2 function appears to maintain genomic stability even when MSH6 staining is abnormal. This finding highlights the central role of MSH2 in regulating the MutSα heterodimer and influencing microsatellite phenotypes\u003csup\u003e\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e. In resource-limited primary care settings, these distinctive staining patterns may provide a practical diagnostic tool for gynecologists to identify high-risk patients who require intensified postoperative follow-up and Lynch syndrome screening.\u003c/p\u003e\u003cp\u003eEmerging reports have documented subclonal expression patterns, with our study identifying 11 such cases demonstrating intratumoral heterogeneity\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e, \u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e, \u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e\u003c/sup\u003e. Subsequent PCR analysis of spatially distinct MMR-IHC expression zones within these tumors confirmed the coexistence of differential microsatellite states. Moreover, previous studies have indicated that heterogeneous staining patterns\u0026mdash;including cytoplasmic, nucleolar, and membranous staining\u0026mdash;are inevitable in MMR IHC evaluation\u003csup\u003e\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e. These variations may be associated with technical factors such as inadequate tissue fixation or degradation in archived paraffin blocks\u003csup\u003e\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. We also observed this phenomenon in our study. Heterogeneous staining was identified in 11 cases in our cohort, most frequently affecting PMS2, probably due to its greater sensitivity to tissue hypoxia and more demanding requirements for optimal fixation\u003csup\u003e\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e\u003c/sup\u003e. Through replacement of paraffin blocks, repetition of IHC staining, and optimization of the staining protocol, these cases were confirmed to show a complete lack of nuclear staining. Therefore, strict adherence to the IHC staining protocol and the consistent use of positive controls are essential for accurate interpretation of PMS2 staining results. Certainly, our study also has some limitations. The relatively small number of cases in the SNS group may limit the generalizability of the findings. Future prospective, multi-center studies with larger cohorts are warranted to validate our proposed SNS criteria. Furthermore, functional experiments are needed to elucidate the precise mechanism by which these mutant proteins influence tumor biology. Long-term follow-up studies are needed to determine the prognostic and predictive significance of the SNS pattern in EC and other cancers, including response to therapies such as immunotherapy, which is often effective in dMMR tumors.\u003c/p\u003e\u003cp\u003eCurrently, immunotherapy is evolving in endometrial cancer\u003csup\u003e\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e, \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. Haider et al. emphasized the importance of categorizing EC into two immunologically distinct subtypes: MSI-H and MSS. They also called for future clinical trials and treatment designs to take these immunological subtypes into account in order to optimize therapeutic outcomes\u003csup\u003e\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u003c/sup\u003e. It is important to accurately distinguish the state of the mismatch repair system. Notably, all cases in our study were postoperatively confirmed as endometrioid adenocarcinoma, predominantly of low grade (grade 1 or 2) and thus would represent the majority of EC cases diagnosed.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eTo our knowledge, the concept of the scattered staining pattern in MMR IHC has not been formally defined in the literature. Here, we present the first study to define and validate this SNS pattern, establishing it as a distinct, reproducible category in MMR IHC interpretation. The identification of the SNS pattern addresses an unmet need in clinical practice and provides a valuable complement to existing CAP guidelines.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cp\u003eIHC \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Immunohistochemistry\u003c/p\u003e\n\u003cp\u003eMMR \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Mismatch repair protein\u003c/p\u003e\n\u003cp\u003eMSI \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Microsatellite instability\u003c/p\u003e\n\u003cp\u003eEC \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;Endometrial carcinoma\u003c/p\u003e\n\u003cp\u003eSNS \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Scattered nuclear staining\u003c/p\u003e\n\u003cp\u003epMMR \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Mismatch repair-proficient\u003c/p\u003e\n\u003cp\u003edMMR \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Mismatch repair-deficient\u003c/p\u003e\n\u003cp\u003eMSI-H \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Microsatellite instability-high\u003c/p\u003e\n\u003cp\u003eCAP \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; College of American Pathologists\u003c/p\u003e\n\u003cp\u003eTCGA \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;the Cancer Genome Atlas\u003c/p\u003e\n\u003cp\u003edMMR/MSI-H \u0026nbsp; Microsatellite-instable/ hypermutated\u003c/p\u003e\n\u003cp\u003eCNH \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Copy number high\u003c/p\u003e\n\u003cp\u003eCNL \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Copy number low\u003c/p\u003e\n\u003cp\u003eNSMP \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;No specific molecular profile\u003c/p\u003e\n\u003cp\u003eMSS \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Microsatellite stability\u003c/p\u003e\n\u003cp\u003ePCR \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; Polymerase chain reaction\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank all the patients and researchers participated in this study.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eQiujuan Huang, Wenxin Liu, Wenfeng Cao:\u0026nbsp;Conceptualization. Yutian Wang, Bo Yang, Lisha Qi, Lin Sun, Ye Luo: Methodology. Qing Li, Jing Luan, Qianru Guo, Manlin Yang: Data curation. Qiujuan Huang: Writing- Original draft preparation.\u0026nbsp;Yuhong Guo, Yalei Wang: Visualization, Investigation.\u0026nbsp;Lingmei Li:\u0026nbsp;Supervision. Lu Cao: Software, Validation.\u0026nbsp;Qiujuan Huang:\u0026nbsp;Writing- Reviewing and Editing. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThis work was funded by the Special Fund for pharmacy, examination, and imaging of Tianjin Medical University Cancer Institute and Hospital (Y2309) and funded by Tianjin Key Medical Discipline Construction Project (Grant No.TJYXZDXK-3-016C).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe data are available from the corresponding author upon reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe study was approved by the\u0026nbsp;Research Ethics Committee of Tianjin Medical University Cancer Institute \u0026amp; Hospital (Number: bc2022174). Written informed consent was waived by the ethics committee. This study was conducted by the Declaration of Helsinki.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSung H, Ferlay J, Siegel RL, et al. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J Clin 2021;71:209-249.\u003c/li\u003e\n\u003cli\u003eUrick ME, Bell DW. Clinical actionability of molecular targets in endometrial cancer. Nat Rev Cancer 2019;19:510-521.\u003c/li\u003e\n\u003cli\u003eColombo N, Creutzberg C, Amant F, et al. ESMO-ESGO-ESTRO Consensus Conference on Endometrial Cancer: diagnosis, treatment and follow-up. Ann Oncol 2016;27:16-41.\u003c/li\u003e\n\u003cli\u003eMarabelle A, Le DT, Ascierto PA, et al. Efficacy of Pembrolizumab in Patients With Noncolorectal High Microsatellite Instability/Mismatch Repair-Deficient Cancer: Results From the Phase II KEYNOTE-158 Study. J Clin Oncol 2020;38:1-10.\u003c/li\u003e\n\u003cli\u003eOaknin A, Tinker AV, Gilbert L, et al. Clinical Activity and Safety of the Anti-Programmed Death 1 Monoclonal Antibody Dostarlimab for Patients With Recurrent or Advanced Mismatch Repair-Deficient Endometrial Cancer: A Nonrandomized Phase 1 Clinical Trial. JAMA Oncol 2020;6:1766-1772.\u003c/li\u003e\n\u003cli\u003eMahdi H, Chelariu-Raicu A, Slomovitz BM. Immunotherapy in endometrial cancer. Int J Gynecol Cancer 2023;33:351-357.\u003c/li\u003e\n\u003cli\u003eKarpel HC, Slomovitz B, Coleman RL, et al. Treatment options for molecular subtypes of endometrial cancer in 2023. Curr Opin Obstet Gynecol 2023;35:270-278.\u003c/li\u003e\n\u003cli\u003eDi Dio C, Bogani G, Di Donato V, et al. The role of immunotherapy in advanced and recurrent MMR deficient and proficient endometrial carcinoma. Gynecol Oncol 2023;169:27-33.\u003c/li\u003e\n\u003cli\u003ePai RK, Plesec TP, Abdul-Karim FW, et al. Abrupt loss of MLH1 and PMS2 expression in endometrial carcinoma: molecular and morphologic analysis of 6 cases. Am J Surg Pathol 2015;39:993-9.\u003c/li\u003e\n\u003cli\u003eChen W, Pearlman R, Hampel H, et al. MSH6 immunohistochemical heterogeneity in colorectal cancer: comparative sequencing from different tumor areas. Human Pathology 2020;96:104-111.\u003c/li\u003e\n\u003cli\u003eSarode VR, Robinson L. Screening for Lynch Syndrome by Immunohistochemistry of Mismatch Repair Proteins: Significance of Indeterminate Result and Correlation With Mutational Studies. Archives of Pathology \u0026amp; Laboratory Medicine 2019;143:1225-1233.\u003c/li\u003e\n\u003cli\u003eBhardwaj A, Marsh WL, Jr., Nash JW, et al. Double immunohistochemical staining with MUC4/p53 is useful in the distinction of pancreatic adenocarcinoma from chronic pancreatitis: a tissue microarray-based study. Arch Pathol Lab Med 2007;131:556-62.\u003c/li\u003e\n\u003cli\u003eAnnese T, Errede M, De Giorgis M, et al. Double Immunohistochemical Staining on Formalin-Fixed Paraffin-Embedded Tissue Samples to Study Vascular Co-option. Tumor Angiogenesis Assays, 2023:101-116.\u003c/li\u003e\n\u003cli\u003eGoodfellow PJ, Billingsley CC, Lankes HA, et al. Combined Microsatellite Instability, MLH1 Methylation Analysis, and Immunohistochemistry for Lynch Syndrome Screening in Endometrial Cancers From GOG210: An NRG Oncology and Gynecologic Oncology Group Study. J Clin Oncol 2015;33:4301-8.\u003c/li\u003e\n\u003cli\u003eWatkins JC, Nucci MR, Ritterhouse LL, et al. Unusual Mismatch Repair Immunohistochemical Patterns in Endometrial Carcinoma. Am J Surg Pathol 2016;40:909-16.\u003c/li\u003e\n\u003cli\u003eRiedinger CJ, Esnakula A, Haight PJ, et al. Characterization of mismatch-repair/microsatellite instability-discordant endometrial cancers. Cancer 2024;130:385-399.\u003c/li\u003e\n\u003cli\u003eKim H, Jen J, Vogelstein B, et al. Clinical and pathological characteristics of sporadic colorectal carcinomas with DNA replication errors in microsatellite sequences. Am J Pathol 1994;145:148-56.\u003c/li\u003e\n\u003cli\u003eCarr C, Son J, Yao M, et al. Clinicopathologic characteristics and outcomes of endometrial Cancer patients with mismatch repair deficiency in the era of universal Lynch syndrome screening. Gynecol Oncol 2020;159:712-720.\u003c/li\u003e\n\u003cli\u003eCosgrove CM, Cohn DE, Hampel H, et al. Epigenetic silencing of MLH1 in endometrial cancers is associated with larger tumor volume, increased rate of lymph node positivity and reduced recurrence-free survival. Gynecol Oncol 2017;146:588-595.\u003c/li\u003e\n\u003cli\u003eBackes FJ, Haag J, Cosgrove CM, et al. Mismatch repair deficiency identifies patients with high-intermediate-risk (HIR) endometrioid endometrial cancer at the highest risk of recurrence: A prognostic biomarker. Cancer 2019;125:398-405.\u003c/li\u003e\n\u003cli\u003eMcMeekin DS, Tritchler DL, Cohn DE, et al. Clinicopathologic Significance of Mismatch Repair Defects in Endometrial Cancer: An NRG Oncology/Gynecologic Oncology Group Study. J Clin Oncol 2016;34:3062-8.\u003c/li\u003e\n\u003cli\u003eNagle CM, O\u0026apos;Mara TA, Tan Y, et al. Endometrial cancer risk and survival by tumor MMR status. J Gynecol Oncol 2018;29:e39.\u003c/li\u003e\n\u003cli\u003eTurashvili G, Hanley K. Practical Updates and Diagnostic Challenges in Endometrial Carcinoma. Archives of Pathology \u0026amp; Laboratory Medicine 2023;148:78-98.\u003c/li\u003e\n\u003cli\u003eShia J, Holck S, Depetris G, et al. Lynch syndrome-associated neoplasms: a discussion on histopathology and immunohistochemistry. Fam Cancer 2013;12:241-60.\u003c/li\u003e\n\u003cli\u003eMangold E, Pagenstecher C, Friedl W, et al. Tumours from MSH2 mutation carriers show loss of MSH2 expression but many tumours from MLH1 mutation carriers exhibit weak positive MLH1 staining. J Pathol 2005;207:385-95.\u003c/li\u003e\n\u003cli\u003eDudley B, Brand RE, Thull D, et al. Germline MLH1 Mutations Are Frequently Identified in Lynch Syndrome Patients With Colorectal and Endometrial Carcinoma Demonstrating Isolated Loss of PMS2 Immunohistochemical Expression. Am J Surg Pathol 2015;39:1114-20.\u003c/li\u003e\n\u003cli\u003eStelloo E, Jansen AML, Osse EM, et al. Practical guidance for mismatch repair-deficiency testing in endometrial cancer. Ann Oncol 2017;28:96-102.\u003c/li\u003e\n\u003cli\u003eKlarskov L, Ladelund S, Holck S, et al. Interobserver variability in the evaluation of mismatch repair protein immunostaining. Hum Pathol 2010;41:1387-96.\u003c/li\u003e\n\u003cli\u003eShia J. Immunohistochemistry versus microsatellite instability testing for screening colorectal cancer patients at risk for hereditary nonpolyposis colorectal cancer syndrome. Part I. The utility of immunohistochemistry. J Mol Diagn 2008;10:293-300.\u003c/li\u003e\n\u003cli\u003eHaron NH, Mohamad Hanif EA, Abdul Manaf MR, et al. Microsatellite Instability and Altered Expressions of MLH1 and MSH2 in Gastric Cancer. Asian Pac J Cancer Prev 2019;20:509-517.\u003c/li\u003e\n\u003cli\u003eScheiderer A, Riedinger C, Kimball K, et al. Reporting Subclonal Immunohistochemical Staining of Mismatch Repair Proteins in Endometrial Carcinoma in the Times of Ever-Changing Guidelines. Archives of Pathology \u0026amp; Laboratory Medicine 2022;146:1114-1121.\u003c/li\u003e\n\u003cli\u003eCasey L, Singh N. POLE, MMR, and MSI Testing in Endometrial Cancer: Proceedings of the ISGyP Companion Society Session at the USCAP 2020 Annual Meeting. International Journal of Gynecological Pathology 2021;40:5-16.\u003c/li\u003e\n\u003cli\u003eJoost P, Veurink N, Holck S, et al. Heterogenous mismatch-repair status in colorectal cancer. Diagn Pathol 2014;9:126.\u003c/li\u003e\n\u003cli\u003eBarrow E, Jagger E, Brierley J, et al. Semiquantitative assessment of immunohistochemistry for mismatch repair proteins in Lynch syndrome. Histopathology 2010;56:331-344.\u003c/li\u003e\n\u003cli\u003eChang CL, Marra G, Chauhan DP, et al. Oxidative stress inactivates the human DNA mismatch repair system. Am J Physiol Cell Physiol 2002;283:C148-54.\u003c/li\u003e\n\u003cli\u003eEskander RN, Sill MW, Beffa L, et al. Pembrolizumab plus Chemotherapy in Advanced Endometrial Cancer. N Engl J Med 2023;388:2159-2170.\u003c/li\u003e\n\u003cli\u003eMirza MR, Chase DM, Slomovitz BM, et al. Dostarlimab for Primary Advanced or Recurrent Endometrial Cancer. N Engl J Med 2023;388:2145-2158.\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-cancer","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcan","sideBox":"Learn more about [BMC Cancer](http://bmccancer.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcan/default.aspx","title":"BMC Cancer","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Endometrial carcinoma, Immunohistochemistry, Scattered nuclear staining, Mismatch repair protein, Microsatellite instability, Immunotherapy","lastPublishedDoi":"10.21203/rs.3.rs-8078986/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8078986/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003eBackground\u003c/h2\u003e\u003cp\u003eImmunohistochemical (IHC) analysis of mismatch repair (MMR) proteins is a widely accepted method for the routine screening of microsatellite instability (MSI) in endometrial carcinoma (EC). However, IHC may occasionally yield indeterminate results, exhibit suboptimal reproducibility, and carry a potential for misdiagnosis. This study aimed to propose a novel MMR IHC expression pattern and explore its clinical significance in EC.\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e\u003cp\u003eFour hundred and seventy-five ECs were characterized using IHC and MSI testing. MMR/CK-pan dual staining confirmed the tumor cell identity of cells exhibiting scattered nuclear staining (SNS). Cases were stratified into four groups based on distinct MMR IHC expression patterns and compared for clinicopathological differences.\u003c/p\u003e\u003ch2\u003eResults\u003c/h2\u003e\u003cp\u003eFour hundred and seventy-five ECs were classified; 75% as mismatch repair-proficient (pMMR) group (intact expression of all 4 MMR proteins, \u0026ge; 5% staining), 13% mismatch repair-deficient (dMMR) group (complete loss of expression of one or more MMR proteins), 2% subclonal group, and 10% as SNS group (\u0026lt;\u0026thinsp;5% staining). The dMMR group were associated with advanced stage, higher grade, presence of lymphovascular space invasion, and significant lymphocyte infiltration around tumor. The SNS group demonstrated aggressive biological behavior similar to, yet distinct from the dMMR group, exhibiting a higher incidence of cervical stromal invasion and lymph node metastasis. MSI testing confirmed that 62.9% of SNS cohort exhibited microsatellite instability-high (MSI-H) status. Different combinations of MMR IHC patterns may provide indicative clues for MSI status.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e\u003cp\u003eSNS represents an objectively identifiable phenomenon within MMR IHC expression patterns and should be recognized as a distinct MMR IHC expression category. The establishment of this pattern not only addresses unmet needs in clinical practice but also complements the existing College of American Pathologists (CAP) guidelines.\u003c/p\u003e","manuscriptTitle":"Scattered Nuclear Staining: A Novel Immunohistochemical Expression Pattern of Mismatch Repair Proteins and Its Significance in Endometrial Carcinoma","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-28 07:07:16","doi":"10.21203/rs.3.rs-8078986/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-31T07:16:36+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-22T14:20:54+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-12-09T11:53:18+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"324530715055960764726419101026746361260","date":"2025-12-01T14:43:31+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"168368555076533519761131118458376681804","date":"2025-11-18T15:55:07+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-18T11:01:35+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-11-13T10:22:18+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2025-11-13T09:21:54+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-11-12T17:38:45+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Cancer","date":"2025-11-12T17:35:28+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-cancer","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"bcan","sideBox":"Learn more about [BMC Cancer](http://bmccancer.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/bcan/default.aspx","title":"BMC Cancer","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"d73247e4-343d-4f1b-b016-ff947bb53231","owner":[],"postedDate":"November 28th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-01-16T08:31:47+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-28 07:07:16","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8078986","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8078986","identity":"rs-8078986","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}